<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html" charset="UTF-8">
    <title>Hello</title>
</head>
<body>
<h1>哈喽！</h1>
<p id="demo"></p>
<button onclick="this.innerHTML=Date()">现在的时间是？</button>
<script>
    //数字
    var len=7;
    //字符串
    var name="gaga";
    //数组
    var cars=["1","2","3"];
    //对象
    var obj={name:"aaa",age:11};
    document.write(obj);
    document.write(typeof "");
    document.write(typeof 7);
    document.write(name.length);
    document.write(name.)

    var x="Liu";
    var y="Liu";
    var z=new String("Liu");
    document.write("\r")
    //比较字符串的值
    document.write((x==y)+"\r"); //true
    document.write((x==z)+"\r"); //true
    //比较字符串的值和类型
    document.write((x===y)+"\r"); //true
    document.write((x===z)+"\r"); //false
</script>
</body>
</html>